Re: juice, in my very limited experience, I've found that Vaperite's organics line pretty amazing. Very clean tasting flavors, not chemical at all (I've tried three so far: blueberry cheesecake, boysenberry, and strawberry shortcake). They're on the subtle side, though, so I don't know if that'd work for you. You can pick up a six flavor sampler for $20, I think.
I'll let the others talk about voltage, because I don't know squat about that. Good luck!